Traditionally, in life jackets provided with one or more buoyancy chambers for supporting the body, the buoyancy chambers are in the form of a collar that wraps around the neck of the user in a horse shoe type configuration that locates the majority of the buoyancy in front of the torso. Attention is directed to United Kingdom patents GB 2,264,903 issued Sep. 15, 1993 to Anthony Male of ML Lifeguard Equipment Ltd and GB 2,089,736 issued Jun. 30, 1982 to Rex Stanley Smith of Lifeguard Equipment Ltd which show examples of such construction.
These known lifejackets have a number of disadvantages. The main buoyancy chambers being located in front of the chest tend to cause the wearer to float in a backwards-leaning position with much of the buoyancy of the inflatable bladder above the surface of the water. This position typically provides little vertical displacement of the mouth and nose above the surface of the water (freeboard) leaving the wearer susceptible to ingestion of water splashed into the mouth by waves and wind which could lead to drowning, especially when unconscious.